FREEPORT (AP) — After a one-year hiatus, heavy trucks are again rumbling through small towns across Maine and Vermont.

A pilot project that allowed trucks weighing up to 100,000 pounds onto interstate highways in the two states ended in December, forcing trucks filled with petroleum, gravel, paper products and other heavy loads back onto state roads that pass through residential areas and business districts.

In this tourist shopping town 15 miles north of Portland, an estimated 100 or more of the trucks roll down Main Street each day, passing by the L.L. Bean flagship store, outlets, restaurants and retail spots while shoppers and tourists amble over crosswalks and cars pull in and out of side streets.

The trucks virtually disappeared from downtown during the pilot, but the interstate weight limit was lowered back to 80,000 pounds two months ago.

Mike Washo has noticed the trucks’ return as they roll past his wine and cigar store, Freeport Trading Co., located on the town’s main drag.

“I think it’s silly they force the trucks to side roads rather than onto the highway, especially when it’s just a quarter-mile away,” Washo said.

But a number of groups, including Advocates for Highway and Auto Safety, Parents Against Tired Truckers, the Coalition Against Bigger Trucks and Public Citizen, are dead set against allowing 50-ton trucks on the interstates.

They argue that the higher interstate weight limits pose a threat to public safety and road and bridge infrastructure. They also say higher weight limits in Maine and Vermont are part of an industry strategy to legalize heavier trucks in all states.

Heavier trucks require more distance to stop, are unwieldy and are more prone to rolling over than lighter trucks, said Jackie Gillan, vice president of the Washington-based Advocates for Highway and Auto Safety. Gillan believes 100,000-pound trucks shouldn’t be allowed at all.

Federal law allows trucks up to 80,000 pounds on federal highways, but a patchwork of exceptions and variations allows heavier trucks on various stretches of different highways in different states.

In Maine, trucks weighing up to 100,000 pounds are allowed on the Maine Turnpike section of Interstate 95 from New Hampshire to Augusta, but the limit is 80,000 pounds on other stretches of interstate. State law, however, allows trucks up to 100,000 on state roads.

The Maine Department of Transportation and the state’s congressional delegation are among the supporters of higher weight limits.

Sens. Susan Collins and Olympia Snowe, of Maine, and Patrick Leahy, of Vermont, have introduced legislation that would permanently allow trucks up to 50 tons on all federal interstates in Maine and Vermont. The current rules put Maine and Vermont at a competitive disadvantage because weight exemptions allow heavier trucks on interstates in New Hampshire, Massachusetts and New York, Collins said.

In the House of Representatives, U.S. Reps. Mike Michaud, of Maine, and Jean Schmidt, of Ohio, have introduced a bill to would allow any state to increase the weight limit on its interstates.

Michaud said his legislation would make Maine companies more competitive and save the state money in road and bridge repair because the heaviest trucks would be diverted to interstates.

He cited a study done by a Bangor trucking company that demonstrated how a higher weight limit could improve efficiency and safety.

The study found a truck traveling about 120 miles from Hampden to Houlton on state Route 2 encountered nine school crossings, four hospitals, 30 street lights, 86 crosswalks and four railroad crossings. The trucker shifted gears 192 times during the trip, applied the brakes 68 times and met 644 other vehicles.

By contrast, a truck making the Hampden-Houlton trip by Interstate 95 didn’t use its brakes, shifted only three times and encountered no schools, street lights, crosswalks, railroad tracks or school buses.

In Freeport, town engineer Albert Presgraves said truck traffic on Main Street is particularly evident in the summer when pedestrian and vehicular traffic picks up, forcing trucks to stop and go and backing up traffic. He doesn’t have accident statistics, but said having huge trucks pass through town seems inherently dangerous.

“Having over 100 trucks come through town each day is a significant number,” he said from office, which looks out onto Main Street.

But opponents maintain that efforts to raise the limits in Maine and Vermont are part of the trucking industry’s strategy to lobby for bigger and heavier trucks in all states.

“The whole purpose of getting higher limits in Maine and Vermont is to start a trend,” said Joan Claybrook, president emeritus of Public Citizen public interest group in Washington. “This is like the camel’s nose under the tent.”